Modern high-speed, subsonic commercial aircraft typically have wings with a variety of leading edge and trailing edge devices to change the shape of the airfoil as the flight conditions change. Such airfoils can include flexible panels at the airfoil leading edge, as disclosed in U.S. Pat. Nos. 3,994,451; 4,171,787; 4,351,502; 4,475,702; and 4,706,913. Other airfoils include flexible trailing edge panels, such as those disclosed in U.S. Pat. Nos. 4,131,253 and 4,312,486.
Other existing devices include variable camber, leading edge Krueger-type flaps, such as those disclosed in U.S. Pat. Nos. 3,504,870; 3,556,439; 3,743,219; 3,910,530; 3,941,334; 4,189,120; 4,189,122; 4,262,868; 4,427,168; 5,158,252; and 5,474,265.
One potential drawback with some of the foregoing devices is that the mechanisms required to actuate the devices can be complex. Accordingly, the cost of installing and maintaining the devices can be relatively high. Another potential drawback is that the devices may not control the airflow over the wing in an optimal manner at all settings. Accordingly, the aerodynamic performance of the airfoils with the leading and/or trailing edge devices deployed may cause some drag increase and corresponding decrease in aircraft performance.